Favors the reduction of androstenedione to testosterone. Uses NADPH while the two other EDH17B enzymes use NADH.

Tissue specificity

Testis.

Pathway

Hormone biosynthesis; testosterone biosynthesis.

Involvement in disease

Defects in HSD17B3 are the cause of male pseudohermaphrodism with gynecomastia (MPH) [MIM:264300]. These individuals have unambiguous female external genitalia at birth, but fail to menstruate at the time of expected puberty and instead virilize as evidenced by growth of the phallus. Breast development may or may not take place.